The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Stephen A Cross - One of the best experts on this subject based on the ideXlab platform.
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determination of superpave gyratory compactor design Compactive Effort for cold in place recycled mixtures
Transportation Research Record, 2003Co-Authors: Stephen A CrossAbstract:Cold in-place recycling (CIR) is a viable pavement rehabilitation technique that recycles 100% of the reclaimed asphalt pavement (RAP) in place, without the addition of heat. One of the barriers to the use of CIR has been the lack of a suitable mixture design procedure. Researchers at the University of Rhode Island have shown that Superpave® mix design technology is applicable to CIR mixtures if the mix design Compactive Effort [number of compaction revolutions or gyrations (Ndesign)] can be established for the Superpave gyratory compactor (SGC). The two objectives of the present project were to determine the mix design Compactive Effort (Ndesign) with the SGC required to match the field densities of CIR mixtures and to evaluate the effect of sample compaction before and after breaking of the emulsion on the Ndesign Compactive Effort. RAPs from seven CIR projects were obtained, as was asphalt emulsion from each project. Samples were compacted with the SGC by use of the mix water and emulsion content from ...
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determination of superpave registered trademark gyratory compactor design Compactive Effort for cold in place recycled mixtures
Transportation Research Record, 2003Co-Authors: Stephen A CrossAbstract:Cold in-place recycling (CIR) is a viable pavement rehabilitation technique that recycles 100% of the reclaimed asphalt pavement (RAP) in place, without the addition of heat. One of the barriers to the use of CIR has been the lack of a suitable mixture design procedure. Researchers at the University of Rhode Island have shown that Superpave mix design technology is applicable to CIR mixtures if the mix design Compactive Effort [number of compaction revolutions or gyrations (Ndesign)] can be established for the Superpave gyratory compactor (SGC). The two objectives of the present project were to determine the mix design Compactive Effort (Ndesign) with the SGC required to match the field densities of CIR mixtures and to evaluate the effect of sample compaction before and after breaking of the emulsion on the Ndesign Compactive Effort. RAPs from seven CIR projects were obtained, as was asphalt emulsion from each project. Samples were compacted with the SGC by use of the mix water and emulsion content from the field. The change in density with the number of compaction revolutions was monitored, and the Ndesign required to match the field density was determined. The effects of RAP physical properties, such as RAP gradation, the percentage of flat and elongated particles, aggregate gradation, and angularity, on Ndesign were evaluated. RAP shape, as measured by the percentage of flaky pieces, was found to influence the compacted field density. The Ndesign Compactive Effort for CIR mix design was also established.
Hussain U Bahia - One of the best experts on this subject based on the ideXlab platform.
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asphalt binder contribution to mixture workability and application of asphalt lubricity test to estimate compactability temperatures for warm mix asphalt
Transportation Research Record, 2013Co-Authors: Andrew Hanz, Hussain U BahiaAbstract:The disconnect between estimated compaction temperatures on the basis of viscosity and behavior observed in laboratory- and field-compacted mixes indicates that the sole use of viscosity is insufficient to characterize the role of the asphalt binder in mixture compaction. The asphalt lubricity test was presented as a complement or replacement to viscosity on the basis of the concept that it was necessary to measure the properties of binders in thin films to relate better to compaction of mixes and to detect the effects of warm-mix asphalt (WMA) additives. To assess the value of the asphalt lubricity test, the relative contributions of lubricity, viscosity, and aggregate gradation on mixture workability at different levels of Compactive Effort were studied with statistical analysis. The mixes included fine and coarse gradations prepared with various conventional and WMA-modified binders, compacted at a range of temperatures representative of those used for WMA. Results indicated that gradation and binder l...
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measuring effects of warm mix additives use of newly developed asphalt binder lubricity test for the dynamic shear rheometer
Transportation Research Record, 2010Co-Authors: Andrew Hanz, Ahmed Faheem, Enad Mahmoud, Hussain U BahiaAbstract:An emphasis on environmental stewardship has prompted the use of warm-mix technologies aimed at allowing for production of conventional asphalt mixtures at reduced temperatures. Successful use of warm-mix asphalt (WMA) in field demonstrations has created a need for development of mix design procedures. A major impediment in development of these procedures is the evaluation of the effect of WMA technologies on asphalt binder and mixture workability. The objective of this study was to introduce a new test methodology for estimating asphalt binder work-ability by measuring the lubricity effects of a surfactant-based additive as well as binder foaming processes through novel use of the dynamic shear rheometer with a new testing fixture. The new test allows measuring the coefficient of friction of binders at various temperatures, loading rates, and normal force. Asphalt binder lubricity measurements were correlated mixture to workability tests defined by the Compactive Effort required to densify a mixture to 8...
Zubairu Abdulhamid - One of the best experts on this subject based on the ideXlab platform.
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Effect of Compactive Effort and Curing Period on the Compressibility Characteristics of Tropical Black Clay Treated with Rice Husk Ash
Geotechnical and Geological Engineering, 2016Co-Authors: Adrian O. Eberemu, Deborah I. Omajali, Zubairu AbdulhamidAbstract:One-dimensional laboratory consolidation test was carried out on compacted tropical black clay (also known as black cotton soil because the cotton plant thrives well on it) treated with up to 16 % rice husk ash (RHA) to assess the effect of Compactive Effort and curing period on the consolidation characteristics of the treated soil. Specimens were compacted using three different Efforts; British Standard Light (BSL), West African Standard, and British Standard Heavy (BSH). Compacted specimen at BSL Effort were also cured for 7, 28 and 56 days before being subjected to one dimensional consolidation tests. The gross yield stress increased with increase in RHA content, curing period and Compactive Effort, ranging from 5 to 26 % between 0 and 56 days curing period and BSL to BSH Effort, respectively. The compression index decreased with increased curing periods (15–40 %), increased Compactive energy (10–55 %) and increased rice husk ash treatment; while the effect of Compactive Effort and RHA treatment was more pronounced in reducing the swell index than the curing period. The variation in coefficient of volume compressibility (Mv) decreases with increased Compactive Effort and curing period irrespective of the loading pressure and RHA content. The Coefficient of consolidation (Cv) generally decreased with increased Compactive energy but showed no observable trend with prolonged curing period irrespective of the RHA treatment.
Andrew Hanz - One of the best experts on this subject based on the ideXlab platform.
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asphalt binder contribution to mixture workability and application of asphalt lubricity test to estimate compactability temperatures for warm mix asphalt
Transportation Research Record, 2013Co-Authors: Andrew Hanz, Hussain U BahiaAbstract:The disconnect between estimated compaction temperatures on the basis of viscosity and behavior observed in laboratory- and field-compacted mixes indicates that the sole use of viscosity is insufficient to characterize the role of the asphalt binder in mixture compaction. The asphalt lubricity test was presented as a complement or replacement to viscosity on the basis of the concept that it was necessary to measure the properties of binders in thin films to relate better to compaction of mixes and to detect the effects of warm-mix asphalt (WMA) additives. To assess the value of the asphalt lubricity test, the relative contributions of lubricity, viscosity, and aggregate gradation on mixture workability at different levels of Compactive Effort were studied with statistical analysis. The mixes included fine and coarse gradations prepared with various conventional and WMA-modified binders, compacted at a range of temperatures representative of those used for WMA. Results indicated that gradation and binder l...
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measuring effects of warm mix additives use of newly developed asphalt binder lubricity test for the dynamic shear rheometer
Transportation Research Record, 2010Co-Authors: Andrew Hanz, Ahmed Faheem, Enad Mahmoud, Hussain U BahiaAbstract:An emphasis on environmental stewardship has prompted the use of warm-mix technologies aimed at allowing for production of conventional asphalt mixtures at reduced temperatures. Successful use of warm-mix asphalt (WMA) in field demonstrations has created a need for development of mix design procedures. A major impediment in development of these procedures is the evaluation of the effect of WMA technologies on asphalt binder and mixture workability. The objective of this study was to introduce a new test methodology for estimating asphalt binder work-ability by measuring the lubricity effects of a surfactant-based additive as well as binder foaming processes through novel use of the dynamic shear rheometer with a new testing fixture. The new test allows measuring the coefficient of friction of binders at various temperatures, loading rates, and normal force. Asphalt binder lubricity measurements were correlated mixture to workability tests defined by the Compactive Effort required to densify a mixture to 8...
Adrian O. Eberemu - One of the best experts on this subject based on the ideXlab platform.
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Effect of Compactive Effort and Curing Period on the Compressibility Characteristics of Tropical Black Clay Treated with Rice Husk Ash
Geotechnical and Geological Engineering, 2016Co-Authors: Adrian O. Eberemu, Deborah I. Omajali, Zubairu AbdulhamidAbstract:One-dimensional laboratory consolidation test was carried out on compacted tropical black clay (also known as black cotton soil because the cotton plant thrives well on it) treated with up to 16 % rice husk ash (RHA) to assess the effect of Compactive Effort and curing period on the consolidation characteristics of the treated soil. Specimens were compacted using three different Efforts; British Standard Light (BSL), West African Standard, and British Standard Heavy (BSH). Compacted specimen at BSL Effort were also cured for 7, 28 and 56 days before being subjected to one dimensional consolidation tests. The gross yield stress increased with increase in RHA content, curing period and Compactive Effort, ranging from 5 to 26 % between 0 and 56 days curing period and BSL to BSH Effort, respectively. The compression index decreased with increased curing periods (15–40 %), increased Compactive energy (10–55 %) and increased rice husk ash treatment; while the effect of Compactive Effort and RHA treatment was more pronounced in reducing the swell index than the curing period. The variation in coefficient of volume compressibility (Mv) decreases with increased Compactive Effort and curing period irrespective of the loading pressure and RHA content. The Coefficient of consolidation (Cv) generally decreased with increased Compactive energy but showed no observable trend with prolonged curing period irrespective of the RHA treatment.
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consolidation properties of compacted lateritic soil treated with rice husk ash
Geomaterials, 2011Co-Authors: Adrian O. EberemuAbstract:One dimensional laboratory consolidation test was conducted on compacted lateritic soils treated with up to 16% rice husk ash (RHA), to assess its consolidation properties. Specimens were prepared at three different moulding water contents (2% dry of optimum, optimum moisture content and 2% wet of optimum) and compacted using the British Standard Light Compactive Effort. Preliminary tests on soils showed improved index properties with an increase in liquid limit (LL), an increase in plastic limits (PL) with a resulting decrease in plasticity index (PI). Preconsolidation pressure increased with RHA content, it also decreased before increasing with increased moulding water content. Reductions in compression index (Cc) and Swell Index (Cs) with increased RHA content were recorded. Cc and Cs generally decreased before increasing with increased moulding water content. The coefficient of volume compressibility (Mv) decreased and increased with higher RHA content; they were also affected by the soil particle state with increasing pressure. The coefficient of consolidation (Cv) showed no observable trend with increased RHA content but generally increased with higher consolidation pressure on the dry and wet side of optimum compacted states.
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performance of cement kiln dust in stabilizing lateritic soil contaminated with organic chemicals
Advanced Materials Research, 2011Co-Authors: Agapitus Ahamefule Amadi, Adrian O. EberemuAbstract:Accidental or deliberate operational discharges of organic chemicals or wastes containing organic chemicals induce geochemical reactions with resultant adverse effects on basic geotechnical properties of the soil. To utilize soil materials from such sites for engineering construction or as foundation soil, stabilization must be carried out. In this study, cement kiln dust (CKD) was applied to lateritic soil contaminated with three different types of commonly occurring organic chemicals namely benzene, ethanol and kerosene to evaluate the restoration and improvements in the engineering properties. Contamination was simulated in the laboratory by adding known quantities (2.5, 5, 7.5 and 10%) of each of the chemicals separately to lateritic soil samples and allowed to air dry for 14 days before stabilizing with 10% CKD. Performance was evaluated on Atterberg limits, compaction characteristics, strength properties and hydraulic conductivity of the contaminated soil. Strength and hydraulic conductivity specimens were compacted with British Standard Light (BSL) Compactive Effort at predetermined optimum moisture content. Results showed that the simultaneous effects of the cementing and pozzolanic action of the CKD rejuvenated the geotechnical properties of the soil, in most cases comparable to the properties at the original pristine condition. Studies on durability and long term competent performance of the stabilized contaminated soil specimens is in progress.